A switchable current source may be used in a wide field of applications from switched mode power supply to LED drivers. One particular application is that of optical proximity sensors. Optical proximity sensors require a special infrared LED driver which has to comply with requirements relating to a wide current trimming range to trim out infrared LED variation, a wide external voltage compliance for different mobile batteries and a fast response time to LED pulse input change for a synchronized proximity engine operation.
It may be desirable to provide an electric circuit of a switchable current source which may be switched fast and reliably to provide a pulsed output current. There is also a desire to provide an electric circuit of a current regulator to provide a fast and reliable sequence of output current pulses. Another desire is to provide a module to generate a switchable output signal which may be turned on and off between a high and low level in a fast and reliable manner.